Contra Costa County, CA Accessory Structures: Shed Rules (2026)

Per Contra Costa County Ordinance Code § 72-6.202, no person may erect, construct, enlarge, alter, or move any building or structure regulated by Title 7 without first obtaining the necessary permits from the county building official. The County applies the 2022 California Residential Code (CRC) exemptions to this requirement: one-story detached accessory structures are exempt from a building permit when the floor area does not exceed 120 sq ft. Even when exempt from a building permit, sheds and playhouses cannot be located within required property setbacks (open space around the perimeter of the property), and approval may be required from the Planning Division, the local Sanitary District, or Contra Costa Environmental Health depending on the structure's location. Electrical, plumbing, and mechanical work to bring utilities such as electricity or water to the shed always requires a permit, as does enclosing mechanical equipment such as a well or pool pump.